A Diesel Engine has the advantage of high thermal efficiency due to operating at high temperature, but it has also the disadvantages of heavy weight, reciprocating unbalance, too much energy loss exhausted to atmosphere, etc.
In the Reciprocating Piston Engine and the Wankel Rotary Engine, there are available pressure gases, not fully expanded in their working chamber at the end of the expansion stroke, and then these pressure gases are exhausted to atmosphere at the next exhaust stroke.
A Gas Turbine has the advantages of low weight, no reciprocating unbalance, continuous power generation, etc., but because it operates at comparatively low temperature, it has also the disadvantage of low thermal efficiency.
The following is a brief description of the Circumferential Piston Pump, a kind of rotary pump, related to this invention.
The pistonlike rotor elements, supported from cylindrical hubs inset into the pump end plate, travel in circular paths in mating body bores. The rotors do not mesh or touch, and fluid seals exist only between rotor and stator surfaces, and not between rotors. It is characteristic of a circumferential piston pump that the rotors do not mesh with, or contact, each other. This is distinguished from lobe, gear, and screw pumps. The radial surfaces and axial-end surfaces of the rotor-piston elements run in clearance contact with the body wall. And load-bearing cotact may exist in these zones. Each rotor in a Circumferential Piston Pump feels the full pumping torque alternatively.
This pump operates at a high compression efficiency under a low compression ratio, and yet it has low compression efficiency under compression ratios higher than "1:2", because high pressure gases compressed by one rotor backflow instantaneously into the pumping chamber of the other rotor which just starts compressing low pressure gases, so the kinetic energy related to backflowing of gases increases the entropy of gases.